NEWS FEATURE

NATURE|Vol 463|21 January 2010

THE REAL HOLES IN CLIMATE SCIENCE
Like any other field, research on climate change has some fundamental gaps, although not the ones typically claimed by sceptics. Quirin Schiermeier takes a hard look at some of the biggest problem areas.

he e-mails leaked from the University of East Anglia’s Climatic Research Unit (CRU) in November presented an early Christmas present to climate-change denialists. Amid the more than 1,000 messages were several controversial comments that — taken out of context — seemingly indicate that climate scientists have been hiding a mound of dirty laundry from the public. A fuller reading of the e-mails from CRU in Norwich, UK, does show a sobering amount of rude behaviour and verbal faux pas, but nothing that challenges the scientific consensus of climate change. Still, the incident provides a good opportunity to point out that — as in any active field of inquiry — there are some major gaps in the understanding of climate science. In its most recent report in 2007, the Intergovernmental Panel on Climate Change (IPCC) highlighted 54 ‘key uncertainties’ that complicate climate science. Such a declaration of unresolved problems could hardly be called ‘hidden’. And some of these — such as uncertainties in measurements of past temperatures — have received considerable discussion in the media. But other gaps in the science are less well known beyond the field’s circle of specialists. Such holes do not undermine the fundamental conclusion that humans are warming the climate, which is based on the extreme rate of the twentieth-

century temperature changes and the inability aerosols and palaeoclimate data — that some of climate models to simulate such warming say deserve greater open discussion, both within without including the role of greenhouse-gas scientific circles and in the public sphere. pollution. The uncertainties do, however, hamper efforts to plan for the future. And unlike the Regional climate prediction myths regularly trotted out by climate-change The sad truth of climate science is that the denialists (see ‘Enduring climate myths’, page most crucial information is the least reliable. 286), some of the outstanding problems may To plan for the future, people need to know mean that future changes could be worse than how their local conditions will change, not currently projected. how the average global temperature will climb. Researchers say it is difficult to talk openly Yet researchers are still struggling to develop about holes in understanding. tools to accurately forecast “Of course there are gaps in climate changes for the twenty“This climate of our knowledge about Earth’s first century at the local and suspicion we’re climate system and its comregional level. ponents, and yes, nothing has The basic tools used to working in is insane. simulate Earth’s climate are been made clear enough to the It’s drowning our general circulation models public,” says Gavin Schmidt, a ability to soberly (GCMs), which represent climate modeller at NASA’s Goddard Institute for Space communicate gaps in physical processes in the gloStudies in New York and one bal atmosphere, oceans, ice our science.” of the moderators and consheets and on the land’s sur— Gavin Schmidt face. Such models generally tributors to the influential RealClimate blog. “But this have a resolution of about 1–3° climate of suspicion we’re working in is insane. in latitude and longitude — too coarse to offer It’s really drowning our ability to soberly com- much guidance to people. So climate scientists municate gaps in our science when some simulate regional changes by zooming in on people cry ‘fraud’ and ‘misconduct’ for the global models — using the same equations, but slightest reasons.” solving them for a much larger number of grid Nature has singled out four areas — regional points in particular locations. climate forecasts, precipitation forecasts, However, increasing the resolution in this